Method for making a bicycle

Abstract

A method for making a bicycle (1) customized for a user is disclosed, comprising the following steps: A. measuring a first height of a bicycle user (1) when he is standing upright; B. measuring a second height of the bicycle user (1) when he is positioned crouched on the tips of his toes with his torso erect and his buttocks in contact with his heels; C. providing a pair of crank arms (20), wherein each crank arm of said pair of crank arms has a length between 70% and 100% of half the difference between said first height and said second height, and wherein said length of each crank arm (20) is not less than 21 cm; D. mounting said pair of crank arms on a bottom bracket (25) of the bicycle (1).

Description

[0001] METHOD FOR MAKING A BICYCLE

[0002] * * *

[0003] TECHNICAL FIELD

[0004] The present invention relates to a method for making a bicycle. In particular, the bicycle can be of a normal type, i.e., equipped with a front wheel and a rear wheel for ground support, or it can be a stationary bicycle, i.e., a exercise bike.

[0005] BACKGROUND ART

[0006] In bicycles, both of the normal type and the stationary type, there is a frame, a bottom bracket associated with the frame, and a pair of crank arms, which are associated with said bottom bracket and in turn constitute a support for a pair of pedals freely hinged to them.

[0007] The crank arms are of particular importance as their length affects the push that the bicycle user must apply to the pedals. In particular, at the same speed, the greater the length of the crank arm, the greater the torque developed and thus the push exerted on the pedals generates greater traction.

[0008] Besides this aspect, the length of the crank arms is a very important parameter for the position assumed by the leg joints, namely the hip, knee, and ankle, and for the resulting biomechanical efficiency and for the improvement of the user's physical condition during the athletic act of pedaling.

[0009] SUMMARY OF THE INVENTION

[0010] An object of the present invention is to provide a method for making a bicycle, whether of a normal or stationary type, that allows for an advantageous positioning of the leg for the biomechanical efficiency and physical condition of the user during the athletic act of pedaling.

[0011] The method according to the invention provides a bicycle capable of facilitating the work of the lymphatic and venous system (i.e., low-pressure or low-circulatory-resistance flows). In particular, such a bicycle allows performing an athletic act with hemodynamic advantages found in systems with low circulatory resistance. This condition allows for the maximum efficiency of low-pressure operating systems by facilitating the work of the lymphatic system and the venous circulatory system. The optimization of their functions allows for a series of advantages also for the cardiovascular system itself, with which they work synergistically, as will become clear in the following.In particular, the invention provides a method for making a bicycle, whether of a normal or stationary type, customized for a user of the bicycle itself. Said method comprises the following steps:

[0012] A. measuring a first height of a bicycle user when he is standing upright;

[0013] B. measuring a second height of the bicycle user when he is positioned crouched on the tips of his toes with his torso erect and his buttocks substantially in contact with his heels;

[0014] C. providing a pair of crank arms, wherein each crank arm of said pair of crank arms has a length between 70% and 100% of half the difference between said first height and said second height, and wherein said length is not less than 21 cm;

[0015] D. mounting said pair of crank arms on a bottom bracket of the bicycle.

[0016] According to another aspect of the invention, in step C said length of each crank arm of said pair of crank arms can be not less than 75%, optionally not less than 80%, more optionally not less than 88% of half the difference between said first height and said second height.

[0017] According to a further aspect of the invention, in step C said length of each crank arm of said pair of crank arms can be not less than 22 cm, optionally not less than 23 cm.

[0018] According to an additional aspect of the invention, in step C said pair of crank arms can be made available by a manufacture thereof.

[0019] According to another aspect of the invention, in step C said pair of crank arms can be made available by a selection thereof from a plurality of pairs of crank arms.

[0020] According to a further aspect of the invention, the method may also comprise the following steps:

[0021] E. making available a frame of the bicycle;

[0022] F. associating said bottom bracket and said crank arms to the frame;

[0023] G. mounting a saddle having an anatomical center on said bicycle frame; wherein a first straight line passing through a center of the bottom bracket and said anatomical center forms, with a second straight line passing through the center of the bottom bracket and extending perpendicular to a surface on which the bicycle rests when in use, an angle greater than or equal to -15° and less than or equal to +30°.

[0024] According to an additional aspect of the invention, said angle can be greater than or equal to -8°.

[0025] According to another aspect of the invention, said angle can be less than or equal to +8°. According to a further aspect of the invention, said angle can be greater than or equal to-2° and / or less than or equal to +2°, optionally equal to approximately 0°.

[0026] According to an additional aspect of the invention, step E can preliminarily comprise measuring a length of the user's legs and the bicycle frame can have a distance from said anatomical center to said center of the bottom bracket not exceeding the difference between said length of the user's legs and said length of each crank arm of said pair of crank arms.

[0027] According to another aspect of the invention, said distance can be equal to double the length of the crank arm, increased by a variable amount from 5cm to 20cm, optionally variable from 10 cm to 15 cm.

[0028] Thanks to the method according to the invention, which leads to a narrow and technically significant range of crank arm lengths, innovative with respect to the teachings of the prior art, a customized bicycle is made available that is capable of increasing, with prolonged training, the athletic abilities of the user, for the same kilometers traveled, thanks to an improvement in venous and lymphatic return.

[0029] These advantages are evident on the basis of the following considerations.

[0030] The two systems in the human body that are relevant to the present discussion are: the heart, which has a pumping function and allows blood to be pushed towards the various peripheral organs, and the muscles, which allow the return of venous blood to the heart. In that context, the arterial vascular bed represents the means for blood transport and distribution to the various organs. The work of these two structures, i.e., heart and muscles, is burdened by a significant effort. By measuring the operating pressures in the systolic and diastolic components, it is possible to evaluate the resistances that the flow encounters to reach the periphery and allow the perfusion of peripheral organs.

[0031] Then there is the glycocalyx, which is the most delicate structure inside the basal wall; it is fundamental for preserving and reducing the resistances to arterial and venous circulation in the vascular bed. The circulatory bed, in fact, is made up of vessels lined by the endothelial layer.

[0032] It has an enormous diffusion, reaching a length four times the circumference of the Earth. The integrity of this entire structure is fundamental for cell nutrition, and it can be argued that the efficiency of the organism fundamentally depends on the integrity of the endothelium and more particularly of the endothelial glycocalyx, which has, among its main functions, the mechanical one of removing red blood cells from the vessel wall, reducing friction and thus improving the transport of oxygen to the cell. The integrity of the endothelial glycocalyx plays a fundamental role, both on a-load friction on the vessel wall and on trauma to the red blood cellwall.

[0033] In addition to these systems, the lymphatic system must be considered, which is constituted by a dense network of lymphatic channels operating in all body structures; they are collected in the lymph nodes and are particularly represented in the abdominal cavity. Inside the abdominal cavity, the lymphatic system represents more than 50%, having an absolute majority role in this location. The main role of the lymphatic system is defense against infections by means of lymph nodes and lymphocytes; another function is the recovery of interstitial proteins and consequently the entire management of the osmosis of interstitial fluids in the cell's activity, i.e., in metabolic activity.

[0034] The lymphatic system is certainly the system with the lowest operating pressures in the human body. It does not have a direct circulation from the heart as happens with the circulation of arterial blood, but its activity is mainly carried out by the muscular pump, by the variations in abdominal pressures (abdominal pump) and by the phasing operated by the respiratory muscles. In the first phase of lymphatic circulation, the main role is given by the major muscles of the skeletal system; then by the pump activity generated by the variation of abdominal pressures, and finally by the negative pressure generated in the thoracic cavity. Through these three functions, the content of the lymphatics returns to the venous circulatory system and only after the cardiac pump does it propose a new cycle.

[0035] This condition makes it the most suitable for evaluating an athletic act having greater efficiency towards low-pressure operating systems. To obtain the maximum facilitation of the lymphatic system, it is necessary for an athletic act to be capable of generating a large muscular push, in conjunction with a reduction in gravitational resistances. A wide athletic gesture with low gravitational resistances and a lack of compression of the main lymphatic trunks by the abdominal organs are the fundamental prerequisites for generating a facilitation of the system and creating advantageous conditions for lymphatic return and its related functions of recovery and transport of lymphatic chyle into the venous circulatory stream.

[0036] Only an athletic act with very low resistance allows the lymphatic system to perform its work in an optimal condition. To better understand this concept, let's take the example of the sphygmomanometer cuff; if the pressure is increased to over 200 mmHg, the arteries, veins, and lymphatics are closed, while lowering the pressure will first free the arteries, then the veins, and finally the lymphatics. This condition makes us understand that only when we reach very low pressures can we also free the lymphatic system. From this derives the need to create an athleticact with low exercise pressures capable of keeping the lymphatic system patent and allowing it to perform its work in the best possible way.

[0037] The proof that the athletic act guarantees a very low-resistance work is precisely the advantage on the drainage of interstitial proteins by the lymphatic system.

[0038] Returning to the venous system, it is substantially a system of collection, i.e., the capacitance bed, of the blood, which is collected in this district before being returned to the heart. In particular, the blood that has reached the periphery gives up its content, through the capillary bed, to the interstitial space which in turn redistributes nutrients to the cells, regulating their metabolic activity. The venous stream collects the blood coming from the capillaries and performs an action of recovering peripheral blood, functioning as a capacitance reservoir for the return of blood and lymph to the heart, to then begin a new cycle.

[0039] The fluids contained in all animal tissues, including humans, are distributed in three different compartments:

[0040] 1) the intracellular compartment;

[0041] 2) the intravascular extracellular compartment, i.e., the plasma;

[0042] 3) the interstitial extracellular compartment.

[0043] A fundamental role for osmotic balance is given by the proteins present in the interstitial space; an excess of these proteins generates an increase in interstitial fluids.

[0044] The interstitial extracellular compartment plays a connecting role between the vascular system and the cell. An athletic act that allows a correct balance of interstitial fluids is fundamental for the optimal functioning of both the circulatory compartment and the metabolic activity of the cell.

[0045] During the rotation of the limbs, a pump effect is realized, through the variation of abdominal pressures. It has been discovered that the maximum efficiency of abdominal variations, i.e., the abdominal pump, is achieved when the rotation of the limbs is greater than 80% of the maximum excursion of the three joints involved, namely hip, knee, and ankle. That maximum excursion corresponds to the difference between the height measured when the user is standing and the height measured when the user is crouched. With the crank arm according to the invention, no less than 70% of that maximum excursion is translated into the distance between the position of the foot at the highest position during pedaling and the position of the foot at the lowest position during pedaling.

[0046] The muscular activity of the lower limbs is fundamental for exerting the abdominal pumpeffect; it plays an important role in facilitating venous and lymphatic circulation within the abdominal organs, especially when the abdominal organs are far from the venous vessels and lymphatic ducts. That condition is obtained when the force of gravity moves the abdominal organs away from the abdominal venous and lymphatic structures, namely in the position of the cyclist stretched out towards the handlebar.

[0047] In addition to the abdominal pump effect, there is also the peripheral venous pump, of which the foot is the engine, being substantially the pump of the periphery. Its function as a pump for venous blood has always been studied in order to improve cardiocirculatory function. In the case of the invention, the venous pump capacity was evaluated by detecting flows with doppler velocimetry on the venous vessels of the foot and in particular on the posterior tibial vein.

[0048] The athletic act obtained with the bicycle made by the method according to the invention involves the hip joint, the knee joint, and the foot joint, i.e., the ankle.

[0049] The athletic act provides for the complete extension of the hip joint operated by the limb in the push phaseand the almost complete retraction of the contralateral limb. The wide gesture is due to the rotation of the crank arm (this rotation is schematically illustrated in figure 1 as a dashed circle) which provides for the use of at least 70% of the interested joints.

[0050] This condition generates a push towards the abdominal wall and a facilitated emptying of the venous and lymphatic vessels of the abdominal cavity. The limb, during rotation, generates a push towards the abdominal wall, facilitating the passage of blood and lymph towards the thoracic cavity.

[0051] The usual position of the cyclist with the spine placed at more than 45° in a prone position with hips and abdominal organs facing downwards, generates a synergistic context with the push in retraction of the retracted limb; this synergy allows maximum facilitation in low-pressure ascending flows that we can summarize in three steps:

[0052] - a first step of push generated by the pump of the foot and the muscles of the limb in extension;

[0053] - a second step of reduction of resistances on the venous and lymphatic compartment operated by the position of the torso with hips and abdominal organs shifted downwards by the force of gravity; and

[0054] - a third step, in which the work of the diaphragm muscle, which is positioned like a pendulum with respect to gravity, is facilitated in generating a negative thoracic pressureand this facilitates the passage of blood and lymph from the abdominal compartment to the thoracic compartment.

[0055] Thanks to the bicycle obtained with the method according to the invention, it has been possible to observe an increase in the variations of abdominal pressures, which determines an improvement in venous and lymphatic return.

[0056] It has been possible to obtain an objective confirmation of the facilitation of the lymphatic system by measuring the ankle circumference after physical exercise and a specific training program. The training program involves a comparison over 10,000 km between traditional pedaling and the pedaling of the bicycle obtained through the invention. The finding was made on several subjects and in all cases, a significant variation in venous pressure was noted, lower with the bicycle obtained through the invention, after physical exercise, and a clear reduction in ankle circumference.

[0057] Furthermore, the study has shown how the application of the plantar push will have maximum effectiveness on the pumping capacity of venous blood when exerted in the midfoot region, at the level of the cuboid bone and more particularly at the level of the calcaneocuboid ligament. We can therefore consider this area the most suitable to guarantee the maximum effectiveness of the foot's venous pump. By positioning the plantar push in the described anatomical context, we will have the optimization of the pump function on the peripheral venous circle.

[0058] Furthermore, the athletic act obtained with such a bicycle minimizes trauma and therefore preserves the integrity of the red blood cell and the structures with which it comes into contact, more precisely the endothelial glycocalyx. Preserving these two structures through an athletic act is of fundamental importance for two reasons: first, because a reduction in the hemolysis of red blood cells is obtained during the athletic act, and second, because in the activity of venous return, the wall of the vessel itself and the venous valves are preserved. A parameter taken into consideration is the measurement of systolic and diastolic pressures having the greatest differential values, a parameter that allows us to evaluate the elastic capacity of the arterial wall after the athletic act.

[0059] Venous pressures have also been evaluated following physical exercise; during the Doppler examination, the measurement of venous pressure on the posterior tibials confirmed the facilitation of venous return.

[0060] The metabolic activity of the liver and pancreas also finds significant advantages. Thefindings on pancreatic circulation can be easily demonstrated by monitoring endocrine pancreatic activity, namely insulinemia and glycemia measured after the athletic act. The advantages, although more complex, can also be measured in the intrahepatic circulation, i.e., of the biliary tract and the portal venous circle.

[0061] The immune activity carried out in this location has a strategic role as the immune system is highly represented in this context; moreover, it represents one of the main entry points for unwanted guests, which is why it is so well represented. We can maintain that optimal conditions of the immune system generate a state of excellent physical fitness.

[0062] BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a schematic side view of a bicycle obtained by the method according to the invention.

[0064] Figure 2 is a schematic side view of a first position assumed by a person in the execution of the method according to the invention.

[0065] Figure 3 is a schematic side view of a second position assumed by a person in the execution of the method according to the invention.

[0066] DETAILED DESCRIPTION OF THE INVENTION

[0067] The present invention will now be described, by way of illustration, but not limitation, according to its preferred embodiments.

[0068] In particular, the method according to the invention is a method for making a bicycle customized for a user.

[0069] Such a bicycle 1 can be a normal type bicycle, i.e., equipped with a rear wheel 10 and a front wheel 15 for ground support, as schematically illustrated in Figure 1, or a stationary type bicycle, i.e., a exercise bike, which differs from the one illustrated in the figures mainly by being positioned on the ground not by wheels, but by support feet, and by comprising a flywheel mass and a braking system for said flywheel mass.

[0070] The method for making the bicycle 1 comprises step A of measuring a first maximum height of a bicycle user when said user, for whom the bicycle is being customized, is standing upright. In particular, that step may provide for the user to be standing upright with their back against a wall, as shown in Figure 2, possibly also with the nape of the neck against the wall, in order to ensure the correct measurement of the user's height.

[0071] Subsequently, the method comprises step B of measuring a second maximum height of the bicycle user when they are positioned crouched on the tips of their feet, with the torso erectand the buttocks substantially in contact with the heels. Alternatively, the leg position can be defined as a position in which the calf is in contact with the thigh, preferably pressed against the thigh. In this case too, to ensure an optimal height measurement, this step may provide for the user to position themselves with their back against a wall, as shown in Figure 3, possibly also with the nape of the neck against the wall. In particular, when an athlete is positioned crouched on the tips of their feet, they are able to keep their buttocks substantially in contact with their heels (Figure 3 shows a slightly earlier phase where the buttocks are not yet in contact with the heels). When, however, the user, due to old age or an injury, is not able to keep their buttocks in contact with their heels when positioned crouched on the tips of their feet, then the buttocks are at a distance from the heels of less than 15 cm, optionally less than 10 cm; however, the invention is specifically intended for users who are able to keep their buttocks substantially in contact with their heels.

[0072] The two height measurements are performed either both barefoot or both with the same footwear on the feet.

[0073] Once these maximum height measurements of the user in the erect and crouched positions have been obtained, the method provides for step C of calculating the difference between the two measured heights and then dividing this difference by two, thus obtaining a value, which, for brevity, is indicated in the following description as the calculated value. Based on this calculated value, the method then provides for making available a pair of crank arms 20 (of which only one is shown in the figures for illustrative purposes of the entire bicycle). In particular, each crank arm of said pair of crank arms has a length between 70% and 100% of the calculated value. The length of the crank arms is not less than 21 cm, optionally not less than 22 cm, more optionally not less than 23 cm.

[0074] Such crank arms can, for example, be rigid, optionally made of a composite material or aluminum.

[0075] The length of each crank arm of the pair of crank arms can advantageously be not less than 75%, optionally not less than 80%, more optionally not less than 88% of the calculated value.

[0076] This means that, in step C, the method according to the invention provides a pair of crank arms 20 in which each crank arm has a length between 70% and 100%, optionally 75% and 100%, of half the difference between the first height and the second height, and in which said length is not less than 21 cm, optionally 22 cm, more optionally 23 cm. In other words, each crank armhas a length equal to the greater of: a) a minimum length not less than 21 centimeters, optionally 22 centimeters, more optionally 23 centimeters; and b) a length between 70% and 100%, optionally 75% and 100%, of half the difference between the first height and the second height.

[0077] Step C can comprise selecting a pair of crank arms having the length determined as described above from a plurality of pairs of crank arms having different lengths, or manufacturing a pair of crank arms having the length determined as described above.

[0078] It is specified that, in the description and in the claims, by length of the crank arm 20 is meant not the maximum length of the crank arm, but the distance between a center of a first hole of the crank arm (not shown in the figures) made at a first longitudinal end of the crank arm and configured to receive a longitudinal end of the bottom bracket 25 of the bicycle 1, and a center of a second hole of the crank arm (not shown in the figures) made at a second longitudinal end opposite the first and configured to receive a fixing pin of a pedal.

[0079] By way of mere example, and not limitation, in the hypothesis that the first height of a bicycle user when the user is standing upright, barefoot, is 170 cm and that the second height of the user when he is positioned crouched on the tips of his feet, with the buttocks substantially in contact with the heels, is 110 cm, the difference between the two measured heights is 60 cm and half of this difference, i.e., the calculated value, is 30 cm. Each of the two crank arms therefore has a length between 70% and 100% of the calculated value, i.e., variable from 21 cm to 30 cm, optionally between 75% and 100% of the calculated value, i.e., variable from 22.5 cm to 30 cm: when equal to 80% of the calculated value, the crank arm length is 24 cm; when equal to 83.3% of the calculated value, the crank arm length is 25 cm; when equal to 88% of the calculated value, the crank arm length is 26.4 cm; when equal to 90% of the calculated value, the crank arm length is 27 cm.

[0080] The crank arm 20 is optionally of the straight type and the central axes of the first hole and the second hole both lie on a longitudinal axis of the crank arm itself.

[0081] The method then provides for step D of mounting said pair of selected or produced crank arms on a bottom bracket 25 of the bicycle.

[0082] Mounting the pair of crank arms on a bottom bracket of the bicycle may provide that the bottom bracket was first installed on a bicycle frame, which frame comprises at least the seat tube or vertical tube, the top tube, and the down tube.

[0083] Mounting the pair of crank arms on the bottom bracket can comprise the step of mounting them angularly spaced by 180°, i.e., facing in diametrically opposite directions, as isthe case in the vast majority of bicycles, or parallel to each other and side by side.

[0084] In addition, mounting the pair of crank arms may provide for inserting a first longitudinal end of the bottom bracket 25 into the first hole of a first crank arm of the pair of crank arms, then locking the first crank arm to said first longitudinal end, and inserting a second longitudinal end of the bottom bracket 25 into the first hole of a second crank arm of the pair of crank arms, then locking the second crank arm to said second longitudinal end.

[0085] In order to mount the crank arms 20 on the bottom bracket 25, for the illustrated embodiment of the bicycle, the method has a step E, preceding step D, of making available a frame 30 of the bicycle (having at least the seat tube or vertical tube, the top tube and the down tube, as indicated above) on which the bottom bracket 25 is installed, or making available a frame 30 of the bicycle without a bottom bracket and installing it in a step indicated as F, to then install the crank arms 20 on the bottom bracket 25.

[0086] It is not excluded that, in an alternative, non-illustrated embodiment, the crank arms could first be mounted on the bottom bracket and then the bottom bracket would be installed on the frame. This option provides that the bottom bracket can be made in two halves that can be fixed to each other, or that the frame can be opened at least at a through hole configured to house the bottom bracket.

[0087] Regardless of when the bottom bracket is installed on the frame, the method according to the invention may provide for a step G of mounting on said bicycle frame a saddle 35 having an anatomical center 40 (schematically illustrated in the figures as an area of the saddle highlighted by an imaginary circle), wherein a first straight line X passing through a center of the bottom bracket, i.e., passing through a central axis, for example of rotation, of the bottom bracket and through said anatomical center 40 forms, with a second straight line Z which passes through the center of the bottom bracket and extends perpendicular to a surface on which the bicycle 1 rests when in use, i.e., on which the rear wheel 10 and the front wheel 15 of the bicycle 1 rest when in use, an angle greater than or equal to -15° and less than or equal to +30° (the angle is considered positive if the first line is inclined towards a front portion of the frame, while it is considered negative if the first line is inclined towards a rear portion of the frame). That is, said angle is comprised between -15° and +30°, where an angle of 0° indicates parallelism (in the present case also overlapping) between the first line X and the second line Z.

[0088] Said angle is optionally greater than or equal to -15° and / or less than or equal to +15°, more optionally greater than or equal to -8° and / or less than or equal to +8°. Advantageously,said angle is approximately 0°, optionally greater than or equal to -2° and less than or equal to +2°.

[0089] It is specified that the anatomical center 40 of the saddle 35 is the point on the saddle on which the user's ischial bones rest. Conventionally, this point is found at the intersection of a symmetry plane of the saddle 35 that divides said saddle into a left half (on which the user's left buttock rests) and a right half (on which the user's right buttock rests) and a section plane, perpendicular to a surface on which the bicycle rests when in use, perpendicular to said symmetry plane of the saddle and positioned where the saddle has a width ranging from 7 cm to 8 cm, optionally about 7.5 cm.

[0090] The first line X and the second line Z advantageously lie on said symmetry plane of the saddle 35, which is perpendicular to the central axis of the bottom bracket 25.

[0091] Furthermore, when the bicycle 1 is in use on a horizontal surface, the second line Z is substantially vertical.

[0092] When the bicycle is of the normal type, the method may provide for making available a frame on which the rear wheel and the front wheel are mounted, or for mounting said wheels on the frame. In this case, the second line Z is substantially perpendicular to a surface on which the wheels of the bicycle rest when in use.

[0093] In the case where the bicycle is of the stationary type, i.e., a exercise bike, the method may provide for making available a frame equipped with feet, or pedestals, or may provide for the step of mounting said feet or pedestals on the frame. In this case, the second line Z is substantially perpendicular to a surface on which the feet or pedestals of the stationary bicycle rest when in use.

[0094] Regardless of the type of bicycle, the step E of making available the bicycle frame may comprise a preliminary step of measuring a maximum length of the user's legs, for example with the user standing upright, as shown in Figure 2, measuring from the ground up to the hip or groin of the user, and then making available a bicycle frame in which the anatomical center 40 of the saddle has a distance from said center (i.e., central axis) of the bottom bracket 25 not exceeding the difference between said length of the user's legs and said length of each crank arm 20 of said pair of crank arms.

[0095] For example, this distance may be equal to double the length of the crank arm 20 increased by a variable amount from 5 cm to 20 cm.

[0096] It is specified that by minimum distance is meant the ratio between a vertical coordinateof the central axis of the bottom bracket and a vertical coordinate of the anatomical center, measured when the bicycle in use is on a horizontal surface.

[0097] Although the lengths of the same user's legs are usually not equal, that difference, amounting to a few millimeters, is negligible compared to the dimensions of the bicycle components, so the length of the user's legs can be indifferently that of the shorter leg or the longer leg, or even an average of the length of the two legs.

[0098] The step of making a frame available may provide for making available a frame that also has a height of said anatomical center 40 of the saddle 35 from said support surface greater than said difference between said first maximum height, measured when the user is standing, and said second maximum height, measured when the user is crouched.

[0099] In particular, the central axis of the bottom bracket 25 has a distance from the support surface such that the distance of the pedal mounted at the end of the crank arm is conventional, and, in detail, the bottom bracket 25 is positioned at a higher elevation when the use of the bicycle requires greater clearance from obstacles, as for example in mountain bikes, and is lower when the use of the bicycle requires greater stability and, therefore, a lower center of gravity of the bicycle 1.

[0100] The method may also provide for a step H of mounting a handlebar 45 on said frame of the bicycle 1.

[0101] According to the method, a distance from said anatomical center 40 of the saddle 35 to said handlebar 42 is variable from 80% to 130%, optionally from 90% to 120%, more optionally from 100% to 115%, of said difference between said first maximum height, measured when the user is standing, and said second maximum height, measured when the user is crouched. Furthermore, a height of the handlebar 45 from a surface on which the bicycle rests during use can be advantageously comprised between 80% and 110% of a height of the anatomical center 40 of the saddle 35 from the same support surface.

[0102] It is specified that in the present discussion when a "rigid" element is defined, it is intended as not appreciably deformable under the normal working loads to which it is subjected. In particular, as opposed to an element defined as "elastic," a rigid body does not primarily perform its function based on its own deformation.

[0103] It should be noted that a bicycle having the frame in which the first line X forms with the second line Z an angle greater than or equal to -15° and less than or equal to +30°, in which said angle is optionally greater than or equal to -15° and / or less than or equal to +15°, moreoptionally greater than or equal to -8° and / or less than or equal to +8°, still more optionally greater than or equal to -2° and less than or equal to +2°, even more optionally equal to about 0°, can be made with a crank arm of any length, even conventional, instead of with a length determined according to steps A, B and C of the method according to the invention. In fact, in this case, the bicycle is still able to facilitate, although to a lesser extent, the work of the lymphatic and venous system.

[0104] In the foregoing, the preferred embodiments have been described and variations of the present invention have been suggested, but it is to be understood that those skilled in the art may make modifications and changes without thereby departing from the relative scope of protection, as defined by the appended claims.

Claims

CLAIMS1. Method for making a bicycle (1) customized for a user, comprising the following steps: A. measuring a first height of a bicycle user (1) when he is standing upright;B. measuring a second height of the bicycle user (1) when he is positioned crouched on the tips of his toes with his torso erect and his buttocks in contact with his heels;C. providing a pair of crank arms (20), wherein each crank arm of said pair of crank arms has a length between 70% and 100% of half the difference between said first height and said second height, and wherein said length of each crank arm (20) is not less than 21 cm;D. mounting said pair of crank arms on a bottom bracket (25) of the bicycle (1).

2. The method according to claim 1, wherein in step C said length of each crank arm (20) of said pair of crank arms is not less than 75%, optionally not less than 80%, more optionally not less than 88% of half the difference between said first height and said second height.

3. The method according to claim 1 or 2, wherein in step C said length of each crank arm (20) of said pair of crank arms is not less than 22 cm, optionally not less than 23 cm.

4. The method according to any of claims 1 to 3, wherein in step C said pair of crank arms (20) is made available by a manufacture thereof.

5. The method according to any of claims 1 to 3, wherein in step C said pair of crank arms (20) is made available by a selection thereof from a plurality of pairs of crank arms.

6. The method according to any of claims 1 to 5, further comprising the following steps: E. making available a frame (30) of the bicycle (1);F. associating said bottom bracket (25) and said crank arms (20) to the frame;G. mounting a saddle (35) having an anatomical center (40) on said frame (30) of the bicycle; wherein a first straight line (X) which passes through a center of the bottom bracket (25) and said anatomical center (40) forms, with a second straight line (Z) which passes through the center of the bottom bracket (25) and which extends perpendicular to a surface on which the bicycle (1) rests when in use, an angle greater than or equal to -15° and less than or equal to + 30°.

7. The method according to claim 6, wherein said angle is greater than or equal to -8°.

8. The method according to claim 6 or 7, wherein said angle is less than or equal to +8°.

9. The method according to claim 6, wherein said angle is greater than or equal to -2° and / or less than or equal to +2°, optionally equal to approximately 0°.

10. The method according to any of claims 6 to 9, wherein step E comprises preliminarily measuring a length of the user's legs and the frame of bicycle (1) at a distance of said anatomical center (40) from said center of the bottom bracket (25) not exceeding the difference between said length of the user's legs and said length of each crank arm (20) of said pair of crank arms.

11. The method according to claim 10, wherein said distance is equal to double the length of the crank arm (20), increased by a variable amount from 5cm to 20cm, optionally variable from 10cm to 15cm.

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